Exception Examples. All examples written by Edith Hemaspaandra and modified by Jessica Bayliss

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1 Exception Examples All examples written by Edith Hemaspaandra and modified by Jessica Bayliss using System; // An example showing how exceptions propogate. public static int divide( int n, int m ) { return n/m; public static int divideself( int n ) { int result = divide( n, n ); public static void Main ( string[] args ) { Console.WriteLine( divideself(3) ); Console.WriteLine( divideself(0) ); // ZeroDivide This produces the following output: 1 An exception System.DivideByZeroException has occurred in test.exe

2 // How to handle the exception in ZeroDivide public static int divide( int n, int m ) { return n/m; catch (ArithmeticException e) { return 0; public static int divideself( int n ) { int result = divide( n, n ); System.out.println( divideself(3) ); System.out.println( divideself(0) ); // ZeroDivide This produces the following output: 1 Arithmetic exception / by zero has been caught. 0

3 // Another way to handle the exception // Put the exception handler in selfdivide public static int divide( int n, int m ) { return n/m; public static int divideself( int n ) { int result; result = divide( n, n ); catch (ArithmeticException e) { result = 0; System.out.println( divideself(3) ); System.out.println( divideself(0) ); // ZeroDivide This produces the following output: 1 Arithmetic exception / by zero has been caught. 0

4 // You can have multiple catch blocks public static int divide( Integer n, Integer m ) { int result = 0; result = n.intvalue() / m.intvalue() ; catch (ArithmeticException e) { catch (NullPointerException e) { System.out.println( NullPointerException + has been caught. ); public static int divideself( Integer n ) { int result; result = divide( n, n ); System.out.println( divideself( new Integer(3) ) ); System.out.println( divideself( new Integer(0) ) ); System.out.println( divideself( null ) ); // ZeroDivide

5 // If you want to handle all exceptions in the same way, // one exception handler (for the superclass Exception) will suffice. public static int divide( Integer n, Integer m ) { int result = 0; result = n.intvalue() / m.intvalue() ; catch (ArithmeticException e) { catch (Exception e) { System.out.println( Exception caught + e.getmessage() ); public static int divideself( Integer n ) { int result; result = divide( n, n ); catch (ArithmeticException e) { result = 0; System.out.println( divideself( new Integer(3) ) ); System.out.println( divideself( new Integer(0) ) ); System.out.println( divideself( null ) ); // ZeroDivide

6 // Creating your own exceptions: you must extend the Exception class public class MeasurementException extends Exception { public MeasurementException( String message ) { super( Measurement error: + message ); // MeasurementException // Now here is the Measurement class that needs this // exception. Note that Measurement won t compile without // the throws clauses. public class Measurement { private double inches; / Creates a measurement set to a specified number of newinches Precondition: the measurement must be >= 0. The measurement is in MeasurementException Occurs is newinches is < 0. / public Measurement( double newinches ) throws MeasurementException { if ( newinches < 0 ) { throw new MeasurementException ( Negative inches in Measurement constructor. ); inches = newinches; / Set the measurement in newinches Precondition: the measurement must be >= 0. The measurement is in MeasurementException Occurs is newinches is < 0. / public void setinches( double newinches ) throws MeasurementException { if ( newinches < 0 ) { throw new MeasurementException ( Negative inches in call to setinches. ); inches = newinches; / Get the measurement in inches. / public double getinches(){ return inches; // Measurement

APCS Unit 5 Exam. Assuming all four classes have a default constructor, which of the following statements would result in an error from the compiler?

APCS Unit 5 Exam. Assuming all four classes have a default constructor, which of the following statements would result in an error from the compiler? APCS Unit 5 Exam Name 1. Suppose we had a superclass called Fruit. The subclasses of this superclass are Apple, Orange, and Banana. Consider the following reference variable declarations. Fruit f; Banana